Lubricant containing hydroabietyl esters



Patented Aug. 14, 1951 UNITED STATES PATENT OFFICE LUBRICANT CONTAINING HYDROABIETYL ESTERS Leslie 0. Beard, Jr., New York, N. Y., and Ralph V. White, Pitman, N. J., assignors to Socony- Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application April 8, 1949,

Serial No. 86,382

9 Claims.

hydroabietyl alcohol is composed of 13-15 per cent of a non-alcohol fraction and the balance is about 15 per cent dehydroabietyl alcohol, 40 per cent dihydroabietyl alcohol and 45 per cent tetrahydroabietyl alcohol. It will be understood that the distribution of the alcohols averages that given hereinbefore but will vary from batch to batch.

The physical properties and composition of hydroabietyl alcohol are as follows:

Hydroxyl value 5.0-5.1 per cent Hydroabietyl alcohol 85-87 per cent Saponification number (diethylene glycol No.) 5-14 Acid number 0.1-0.4 Methoxyl value 0.5-1.2 Unsaturation, weight per cent:

By hydrogen absorption 0.60-0.75 By bromine number 12-30 Color (50-min. tube) Lovibond 0.5 amber U. S. Rosin Standard Z7 Softening point (drop method) 33 C. Specific gravity at 20/20 C 1.007-1.008 Refractive index at 20 C 1.528 Flash point (C. O. C.) 185-195 C. Flame point (C. O. C.) 217-220 C.

It has been said that the chemical reactions of hydroabietyl alcohol are typical of a primary monohydric alcohol plus what might be expected from the residual unsaturation in the ring structure. Nevertheless, it has been found that as an additive to mineral oil to produce a compounded mineral oil for use as a gear lubricant or a cutting oil or a turbine oil, the similarity between esters of hydroabietyl alcohol and esters of a primary monohydric aliphatic alcohol ceases to exist. It is true that hydroabietylalcohol reacts with monoand dicarboxylic acids to produce esters but the similarity between hydroabietyl alcohol and oleyl alcohol, for example, ceases at that point. However, before discussing the marked difierence between esters of hydroabietyl alcohol and esters of alcohols such as oleyl alcohol, it is desirable to emphasize the structure of the alcohols present in hydroabietyl alcohol. It also is to be noted that the non-alcohol portion of hydroabietyl alcohol varies with the saponification number but will average 3-8 per cent of esters which can be considered as methyl esters of hydrogenated rosin and the remainder 7-12 per cent is similar to the hydrocarbon fractions occurring in hydrogenated rosin. Thus, the product, esters of hydroabietyl alcohol, may give the 5 improved results to be discussed hereinafter because of the structure of the alcohol, because of the degree of unsaturation of the major portion of the alcohol fraction or for other reasons at present unknown.

The three alcohols present in hydroabietyl alcohol have the following structures:

CH: CHzOH CH: CHzOH CH3 cm Dehydroabietyl alcbol CH: CH:

Dihydroabietyl alcodol CH: CHiOH Tetmhydroabietyl alcohol It will be noted that in each alcohol the hydroxyl group is attached to the nucleus through a methylene, CH2, group. It also will be noted that an isopropyl group and two methyl groups are attached to the nucleus. Although 45 per cent of the abietyl alcohols present is a saturated alcohol the balance is alcohols of two degrees of unsaturation. Consequently, the major portion of the alcohol portion of hydroabietyl alcohol is alcohols having one and three oleflnic double bonds.

It has been found that esters prepared from the commercial hydroabietyl alcohol and hydroxy aliphatic polycarboxylic acids are useful as rust inhibitors in turbine oils and as extreme pressure additives in lubricants such as gear oils. Typical esters are di-hydroabietyl malate, dihydroabietyl tartrate, tri-hydroabietyl citrate, hydroabietyl-2-ethylhexyl malate, hydroabietyl- 2-ethylhexyl tartrate, di-hydroabietyl-2-ethylhexyl citrate, hydroabietyl-di-2-ethylhexyl citrate, hydroabietyl-oleyl malate, hydroabietyloleyl tartrate, di-hydroabietyl-oleyl citrate, hydroabietyl dioleyl citrate, and similar esters of hydroxy aliphatic polycarboxylic acids in which all of the carboxyl groups are esterified with hydroabietyl alcohol or in which one carboxyl group of a dicarboxylic acid is esterified with hydrowater of reaction had been separated. The solvent was then removed by gradually reducing the pressure in the reactor. The solvent-free product was warmed to 130 C., and filtered to remove abietyl alcohol and the other carboxyl group is 5 solids. The filtered product had a neutralization esterified with a monohydric aliphatic saturated number of 13.3 indicative of neutral ester content or unsaturated straight chain or branched chain of about 89 per cent. alcohol of at least 8 carbon atoms or 1 or two Hydroabietyl-Z-ethylhexy1 malate was precarboxyl groups of a tricarboxylic acid are esteripared in a manner similar to that employed in fied with hydroabietyl alcohol and the others 10 preparing di-hydroabietyl malate by reacting 0.5 esterifled by a monohydric saturated or unsatumole of hydroabietyl alcohol, 0.5 mole Z-ethylrated straight or branched chain monohydric hexanol and 0.5 mole dl-inalic acid. The filtered alcohol of at least 8 carbon atoms. It is to be product had a neutralization number of 19.9 inunderstood that the term hydroabietyl alcohol dicative of a neutral ester content of about 88.6 is used herein to designate the mixture of alcoper cent. hols, esters and hydrocarbons discussed herein- Hydroabietyl oleyl malate was prepared from before. 0.375 mole of hydroabietyl alcohol, 0.375 mole of In determining the amount of hydroabietyl aloleyl alcohol and 0.375 mole of dl-malic acid. The cohol to be reacted with a predetermined amount filtered product had a neutralization number of of polycarboxylic acid, it is necessary to bear in 16.0 indicative of a neutral ester content of about mind that the presently available commercial hy- 88 per cent. droabietyl alcohol is, as pointed out hereinbefore, Each of the foregoing products was subjected a mixture of alcohols, esters and hydrocarbons. to the A. S. T. M. Test D665-44T. In this test, Consequently, the amount of the mixture ema cylindrical polished steel specimen is suspended ployed will be dependent upon the hydroxyl numand soaked in 300 milliliters of the test oil at her of the available commercial hydroabietyl al- 140 F., for minutes. Thirty milliliters of discohol. One gram molecular weight of hydrotilled water are added then and the mixture is abietyl alcohol contains 17 grams of the hydroxyl stirred at 1000 R. P. M. After 48 hours the steel group. A determination of the hydroxyl number specimen is removed and examined for evidence of the commercial hydroabietyl alcohol used in 30 of rust. The oil is rated as passing when there the preparations discussed hereinafter estabis no evidence of rust on that part of the specimen lished that 341 grams of that commercial hydrowhich han belOW the O labietyl alcohol contained 17 grams or the hy- The test oil for the anti-rust tests was a blend droxyl group. Therefore, for each mole of polyof solvent-refined Mid-Continent residual stock carboxylic acid employed in the preparation of with a solvent-refined Mid-Continent distillate an ester 17 grams of hydroxyl group are required t e blend has & Spe fic a y of for each carboxyl group to be esterified by the a a h point 0f R, and y hydroabietyl alcohol. Consequently, when pre- Universal viscosity of 407.7 seconds at 100 F. paring dihydroabiety] malate from 0.375 l of This oil is suitable for use in steam turbines. In -malic acid 0. 5 mole of hydroabietyl alcohol addition to the esters to be tested the oil blend is required. Since 341 parts by weight of comcontained -2 p r cent of ditertiary' butyl ra mercial hydroabietyl alcohol having a hydroxyl CIESOI and per cent of phenyl alpha naphthyl" value of 5% contains 17 parts by weight of hyamine. These antioxidants may be replaced by droxyl group, it follows that 0.375 mole of malic Other Su table ant oxidants. acid require of 341 or 255.7 parts by weight The oils which were subjected to the anti-rust of commercial hydroabietyl alcohol. test were also subjected to the Emulsion Test for Di-hydroabietyl malate was. prepared by ma Lubricating Oils described in the Federal Stool: ing 0.75 mole (255.7 g.) commercial hydroabietyl C l u ti n IV. art F deral p ifi aalcohol and 0.375 moleof dl-malic acid in a contiOn VV-L791b (February 19, 1942) i In the tes tainer provided with a thermometer, a mechani- 320.13, 40 milliliters of the oil: blend to be tested cal stirrer and a reflux condenser provided with a D0 and 40 milliliters of emulsant are. stirred for 5 water take-01f. The mixture. was heated to 130- utes Wit a paddle at 1500 R- in a 135 C. and digested in that temperature range for milliliter g aduat d cyl at 1 about 0.5 hour. The reflux water take- 1f w s tion of the emulsion is observed while the cylfilled with benzene and an amount of benzene inder is maintained at 130 F. The number of added to the reaction mixture such that the ben- 55 minutes required for the disappearance of a conzene refluxed while the contents of the reactor tinuous layer of emulsion between the oil and the were at 130-135 C. (Any other solvent forming emulsant is recorded. an azeotroplc mixture with water can be used.) The results of the tests described hereinbefore Alter refluxing for 6 hours 93 per cent of the are recorded in Table I.

TABLE I t i' e it Anti-rust es 0 (Method 320.13) new Agent 653%.? itltii thii Minutes to break Pgiglelzgt tilled Water airrt'ztatrts. .1: 3:32 -iiittiffiii: l2 l2 HydroabietylOleylMalato 0.25 .do 17 19 Base Oil (witl or without oxi- 0.00 fail (severe rust)... Y 2 1 datlon mhlbltors).

1 Octylis Z-cthylhexyl.

These and similar esters may be used in cutting oils. the base oil of a cutting oil may be a sulfurized mineral oil, a sulfurized and a chlorinated oil combined with mineral oil of suitable viscosity and additives included for various purposes. Thus, for example, a cutting oil may have the following compositions.

Broad Preferred Formula Formula CUTTING OIL NO. 1

Moderately suliurized mineral oil contg about 09% active sulfur; per cent -99 30-99 Chlorinated base contg about 42% chlorine;

per cent 0-l5 0-7 Mineral Oil 50-500 100 F. SUV; per cent. 0-99 0-62 Hydroabietyl ester of alpha-hydroxyl aliphatic poly-carboxylic acid 0. 1-10 0. 25-2 CUTTING OIL NO. 2

Sulfurized-chlorinated fatty oil contg about 5% sulfur and about 5%chlorine; per cent... 0. 25-15 0. 5-4. 0 Mineral oil. 50-500 100 F., SUV; per cent. 78-99 95-99. 0 Stain Inhibitor; per cent 0-2 0.1-0. 5 Hydroabietyl ester of alpha-hydroxy aliphatic polycarboxylic acid; per cent 0.1-5 0. 25-0. 6

Blends within the ranges set forth hereinbefore were made and subjected to several tests to determine the effectiveness of the novel hydroabietyl esters in comparison with prior art additives which have proved efiective. The blends were subjected toa tapping test, the Oster threading test and a drill life test.

Tapping test In the measurement of tapping emciency of an oil, a series of holes are very accurately drilled in a test metal, namely SAE-1020 steel. These holes are subsequently tapped with a series of taps, in a drill press equipped with a table, which is free to rotate about the center, being mounted on ball bearings. A torque arm is attached to this "floating table and this arm in turn actuates a spring scale so that the actual torque during tapping with the oil being evaluated is measured directly. The same taps used in evaluating the test oil are employed in tapping with a standard reference oil, which has arbitrarily been assigned an efiiciency of 100 per cent. The average torque for the test oil is compared to that of the standard and a relative efficiency is calculated on a percentage basis. For example:

Torque with standard reference oil 19.3 Torque with test oil 19.8

Relative eiiiciency of test oil It might be added that the cutting oils are applied to the taps by means of a circulation system.

Oster threading test As is well known to those skilled in the art 8 arbitrarily assigning an efliciency or percent to the reference oil and calculating the comparative efliciency of the unknown on a power'requirement basis.

- Drill life test The drill life test is determined by using ten' drills ground to specified angles, three of which are placed in the chucks of a triple spindle head of the drill press. Holes are then drilled through flats of SAE 3140 steel until drill failure occurs. This is evidenced by excessive noise, tool burning and deterioration at the cutting edges. The failed drill is replaced with .a newly ground one and the test is continued until all ten drills fail. The drill life is the average of the number of holes obtained per drill before failure.

The data obtained when subjecting 5 blended oils and a control to the foregoing tests are tabulated in Table II.

TABLE II Weight Per Tapping gggg i Drill Life, Additive Cent Cone. Efiiciency, Emcienc g Number of of Additive Per Cent Per Holes H0 I 102 79 E00 l 102 100 DIH 1 101 101 Additive HO comprised the hydroabietyl oleyl malate prepared as described hereinbefore.

, Additive HOC comprised the hydroabietyl octyl (2-ethylhexyl) malate prepared as described hereinbefore.

Additive DIH comprised the di-hydroabietyl malate prepared as described hereinbefore.

Additive DAM comprised the neutral malate ester of an uiisaltulrated high molecular weight aliphatic monohydric a co 0 Additive MAM comprised a compound ester in which both carboxyl groups of malic acid are esterified by a monoglycol ester of a high molecular weight aliphatic monocarboxylic acid.

Judged by the results of the tapping and threading emciency tests the novel hydroabietyl alcohol esters are comparable to the other esters. However, the efiectiveness of the novel esters in actual drilling tests is remarkable. This is to say, while one of the best of the ester-type additives (DAM) only increases the life of a drill about 26% the novel esters increase the life of a drill 55% where R is a high molecular weight olefinic radical.

Ester H0 has the following structure:

where R is a high molecular weight olefinic radical and R" is the radical from the hydroabietyl alcohol mixture.

Thus, although the only apparent difference between the esters is the substitution of a hydroabletyl radical for. one of the partially esterified dihydric alcohol radicals, the novel ester is about twice as efilcient as the prior art ester-type additive.

-While the tapping, threading and drill life tests indicate that esters having both carboxyl groups of an hydroxy aliphatic polycarboxylic acid esterified with radicals from hydroabietyl alcohol mixture are all more effective than. similar esters of aliphatic alcohols, there is an advantage to the use of either mixed esters or mixtures of esters. This advantage results from the viscosity of the various esters. As is manifest after a consideration of the following tabulation of viscosities of. various esters, di-hydroabietyl malate, for example, is far more viscous than the mixed esters. The high viscosity of the di-hydroabietyl esters makes it desirable to reduce the viscosity without sacrificing a disproportionate amount of the effectiveness of the hydroabietyl esters. As will be appreciated by study of the following tabulation this can be done by using mixed esters.

Consequently, for ease of manufacture and incorporation in oil blends it is preferred to employ a mixed ester of an alphahydroxy polycarboxylic acid derived from 50 mole per cent of hydroabietyl alcohol (based upon the hydroxyl number of alcohol mixture) and 50 mole per cent oleyl alcohol, i. e.,. from the reaction of 1 mole of hydroabietyl alcohol, 1 mole of oleyl alcohol and 1 mole of polycarboxylic acid. Fluidity of the product can be obtained by employing mixed esters of alpha-hydroxy polycarboxylic aliphatic acids in which from 50 mole per cent to 100 mole per cent hydroabietyl radical and from 1 to 50 mole per cent of an alkyl radical are present in the carbalkoxy groups (carbalkoxy being inclusive of carbcycloalkoxy). The alkyl groups are those derived from monohydric aliphatic saturated or unsaturated alcohols having'from one through 18 carbon atoms and includes oleyl alcohol.

Mixed esters containing 75 mole per cent hydroabietyl 25 mole per cent oleyl ester may be made in any of the following or other suitable procedures.

A. Hydroabietyl alcohol (about 1.5 moles), oleyl alcohol (about 0.5 mole) and alpha-hydroxy aliphatic polycarboxylic acid (about 1.0 mole) are reacted as described hereinbefore.

B. About I5 mole parts of di-hydroabietyl ester of an alpha-hydroxy aliphatic polycarboxylic acid and about 25 mole parts of di-oleyl ester of an alpha-hydroxy aliphatic polycarboxylic acid are heated together until ester exchange has occurred.

C. Equal parts of 85 mole per cent hydroabietyl-15 mole per cent oleyl ester of an alpha-hydroxy aliphatic polycarboxylic acid and of 65 mole per cent hydroabietyl-35 mole per cent oleyl ester of an alpha-hydroxy aliphatic polycarboxylic acid are heated together until ester exchange has occurred.

D. A mechanical mixture is made of anhydroabietyl ester of an alpha-hydroxy aliphatic polycarboxylic acid and an ester of an alphahydroxy aliphatic polycarboxylic acid and a. monohydric aliphatic alcohol having 8 to 20 carbon atoms in the proportion to produce the desired viscosity and the mixture added to the oil to be fortified.

In the foregoing the amount of hydroabietyl alcohol employed is based upon the hydroxyl number of the available mixture containing the hydroabietyl alcohol. That is to say, one mole of alcohol is equivalent to 17 grams of hydroxyl radical.

It is to be noted that while the neutral esters are satisfactory for use in cutting oils it is preferred to use esters which are a mixture of neutral and partial esters for anti-rust agents. Therefore, it is preferred to use esters having a neutralization number of zero to 30 in cutting oils but esters having a minimum neutralization number of 10 in anti-rust oils, such as turbine oils.

Those skilled in the art will understand that when compounding base oils with the novel esters other additives such as antioxidants, pour depressants, stain inhibitors, etc. etc., may be added in addition to the novel ester. Accordingly, the present invention contemplates the addition of the novel esters to simple or compound mineral oils of lubricating grade in the proportion of about to about 99 per cent by weight of base oil to about 10 to l per cent, preferably 0.1 to 2 per cent by weight of the novel ester. In other words, the present invention provides a novel composition of matter comprising a major proportion of a base oil and a minor proportion of the novel esters effective to inhibit rusting and to enhance the extreme pressure properties of the base oil. The base oil is a lubricating fraction of mineral oil, a conventional gear lubricant base, a cutting oil or a grease.

We claim:

1. A novel composition of matter comprising moderately sulphurized mineral oil containing about 0.9% ctive sulphur, 0-99 weight percent; chlorinated base containing about 42% chlorine, 0-15 weight percent; mineral oil 50-500" 100 F. SUV, 0-99 weight percent, and about 0.1 to 10 weight percent of an ester product of malic acid in which about 50-100 mole percent of the radicals attached to the carbonyl carbon atoms through oxygen is radicals of hydroabietyl alcoho-l and the balance is a radical of a monohydric' aliphatic alcohol having 8-20 carbon atoms.

2. A novel composition of matter comprising sulphurized and chlorinated fatty oil containing about 5% sulphur and about 5% chlorine, 0.25 to about 15 weight percent; mineral oil, 50-500" 100 F. SUV, about '78 to about 99 weight percent; stain inhibitor, 0.1 to 10 weight percent of an ester product of malic acid in which about 50-100 mole percent of the radicals attached to the carbonyl carbon atoms through oxygen is radicals of hydroabietyl alcohol and the balance is a radical of a monohydric aliphatic alcohol having 8-20 carbon atoms.

3. A novel composition of matter consisting essentially of a major proportion of a base oil of petroleum origin and. a minor proportion about 0.1 to about 10 percent by weight of an ester product of malic acid in which about 50-100 mole percent of the radicals attached to the carbonyl carbon atoms through oxygen are radicals of hydroabietyl alcohol and the balance is a radical of a monohydric aliphatic alcohol having 8-20 carbon atoms.

4. A novel composition of matter consisting essentially of a major proportion of a base oil of petroleum origin and a minor proportion efiective to increase the oiliness of said base oil of a mixture of hydrogenated rosin hydrocarbons and an ester product of malic acid in which about 50-100 mole percent of the radicals attached to the carbonyl carbon atoms through oxygen is radicals of hydroabietyl alcohol and the balance is a radical of a monohydric aliphatic alcohol having 8-20 carbon atoms.

5. A novel composition of matter comprising:

Component- Per cent weight Moderately sulfurized mineral oil 30-99 Chlorinated base containing about 42% chlorine 7 Mineral oil, 50-500" 100 F. SUV 0-62 Ester product of malic acid in which about 50 to 100 mole per cent of the radicals attached to the carbonyl carbon atom through oxygen is radicals of hydroabietyl alcohol and the balance is a radical of monohydric aliphatic alcohol having 8-20 carbon atoms 0.25- 2 6. A novel composition of matter comprising:

Component- Per cent weight Sulphurized-chlorinated fatty oi1 0.25-15 Mineral oil, 50-500" 100 F. SUV 78-99 Stain inhibitor 0- 2 Ester product of malic acid in which about 50-100 mole per cent of the radicals attached to the carbonyl carbon atoms through oxygen is radicals of hydroabietyl alcohol and the balance is a radical of a monohydric aliphatic alcohol having 8-20 carbon atoms", 0.1

7. A novel composition of matter comprising:

Component Per cent weight Sulphurized-chlorinated fatty oil 0.5 -4.0 Mineral oil, -500" 100 F. SUV 99 Stain inhibitor 0.1 -0.5 Ester product of malic acid in which about 50-100 mole per cent of the radicals attached to the carbonyl carbon atoms through oxygen is radicals of hydroabietyl alcohol and the balance is a radical of monohydric aliphatic alcohol having 8-20 carbon atoms 025-05 8. A novel composition of matter consisting essentially of a base oil of petroleum origin and a minor proportion about 0.1 to about 10 weight per cent of a mixture of 1) a half ester of malic acid and hydroabietyl alcohol and (2) a half ester of malic acid and an aliphatic monohydric alcohol having 8-20 carbon atoms in the molecule.

9. A novel composition of matter consisting essentially of a base oil of petroleum origin and a minor proportion about 0.1 to about 10 weight per cent of a mixture of (1) a half ester of malic acid and hydroabietyl alcohol and (2) a half ester of malic acid and an aliphatic monohydric alcohol having 8-20 carbon atoms in the molecule, said mixture of said half esters having been heated until ester exchange occurs.

LESLIE C. BEARD, JR. RALPH V. WHITE.

REFERENCES CITED The following references are of record in the file oi! this patent:

UNITED STATES PATENTS Number Name Date 2,142,989 Barrett Jan. 10, 1939 2,384,595 Blair Sept. 11, 1945 2,397,332 Amott Mar. 26, 1946 2,436,272 Snyder Feb. 17, 1948 2,443,579 Fuller June 15, 1948 OTHER REFERENCES New Products and Materials, Chem. Eng, January 1948. Copy in Div. 50.

Certificate of Correction Patent No. 2,564,634 August 14,1951

LESLIE C. BEARD, JR., ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requirlng correction as follows: Y

Column 2, line 22, for Dehydroabietyl alchol read Dehydroabz'etg Z alcohol; same line, for Dihydroabietyl alcodol read Dz'hg/droabz'etylalcokol; column 7, in the heading to the table, columns 4 and 5 thereof, for

Viscosity SUV (see) At 130' F. At 210 F.

column 8, line 6, for anhydroread an kyclrm;

and that the said Letters Patent should be read as corrected above, so'fv that the same may conform to the record of the case in the Patent Officel' Signed and sealed this 1st day of January, A. D. 1952.

THOMAS F. MURPHY,

Assistant Oommz'asz'oner of Patents. 

1. A NOVAL COMPOSITION OF MATTER COMPRISING MODERATELY SULPHURIZED MINERAL OIL CONTAINING ABOUT 0.9% ACTIVE SULPHUR, 0-99 WEIGHT PERCENT; CHLORINATED BASE CONTAINING ABOUT 42% CHLORINE, 0-15 WEIGHT PERCENT; MINERAL OIL 50-500" @ 100* F. SUV, 0-99 WEIGHT PERCENT, AND ABOUT 0.1 TO 10 WEIGHT PERCENT OF AN ESTER PRODUCT OF MALIC ACID IN WHICH ABOUT 50-100 MOLE PERCENT OF THE RADICALS ATTACHED TO THE CARBONYL CARBON ATOMS THROUGH OXYGEN IS RADICALS OF HYDROBIETYL ALCOHOL AND THE BALANCE IS A RADICAL OF A MONOHYDRIC ALIPHATIC ALCOHOL HAVING 8-20 CARBON ATOMS. 